Eight days after we published my investigation on how more than a ton of cocaine was being flown daily out of the world’s No. 1 coca-producing valley right under the Peruvian military’s nose, we have a significant development.

For the first time in more than a decade, an officer of Peru’s armed forces has been arrested for drug trafficking. An army lieutenant, he had worked in the valley for eight years and collected bribes of $10,000 per flight that likely were shared with his superiors, the prosecutor told me. That’s the same sum that an accused narco pilot had told me local military commanders got per plane.

Former Peruvian army Maj. Evaristo Castillo, who blew the whistle on military drug trafficking in the 1990s, says drug corruption is _ as it was then _ systematic in the military, as top to bottom as the command structure.

One arrest is no guarantee of a housecleaning. Just ask Castillo. None of the generals he publicly denounced for drug trafficking was ever convicted of it, he told me. Castillo’s military career was wrecked because he blew the whistle, was disloyal. He spent seven years in exile. And, as one of his four sons (also Evaristo), told me, their hopes of following their father into the service were also extinguished.